472 lines
9.5 KiB
Perl
472 lines
9.5 KiB
Perl
#
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# Module Parse::Yapp::Driver
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#
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# This module is part of the Parse::Yapp package available on your
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# nearest CPAN
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#
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# Any use of this module in a standalone parser make the included
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# text under the same copyright as the Parse::Yapp module itself.
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#
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# This notice should remain unchanged.
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#
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# (c) Copyright 1998-2001 Francois Desarmenien, all rights reserved.
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# (see the pod text in Parse::Yapp module for use and distribution rights)
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#
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package Parse::Yapp::Driver;
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require 5.004;
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use strict;
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use vars qw ( $VERSION $COMPATIBLE $FILENAME );
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$VERSION = '1.05';
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$COMPATIBLE = '0.07';
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$FILENAME=__FILE__;
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use Carp;
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#Known parameters, all starting with YY (leading YY will be discarded)
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my(%params)=(YYLEX => 'CODE', 'YYERROR' => 'CODE', YYVERSION => '',
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YYRULES => 'ARRAY', YYSTATES => 'ARRAY', YYDEBUG => '');
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#Mandatory parameters
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my(@params)=('LEX','RULES','STATES');
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sub new {
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my($class)=shift;
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my($errst,$nberr,$token,$value,$check,$dotpos);
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my($self)={ ERROR => \&_Error,
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ERRST => \$errst,
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NBERR => \$nberr,
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TOKEN => \$token,
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VALUE => \$value,
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DOTPOS => \$dotpos,
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STACK => [],
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DEBUG => 0,
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CHECK => \$check };
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_CheckParams( [], \%params, \@_, $self );
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exists($$self{VERSION})
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and $$self{VERSION} < $COMPATIBLE
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and croak "Yapp driver version $VERSION ".
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"incompatible with version $$self{VERSION}:\n".
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"Please recompile parser module.";
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ref($class)
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and $class=ref($class);
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bless($self,$class);
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}
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sub YYParse {
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my($self)=shift;
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my($retval);
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_CheckParams( \@params, \%params, \@_, $self );
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if($$self{DEBUG}) {
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_DBLoad();
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$retval = eval '$self->_DBParse()';#Do not create stab entry on compile
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$@ and die $@;
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}
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else {
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$retval = $self->_Parse();
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}
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$retval
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}
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sub YYData {
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my($self)=shift;
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exists($$self{USER})
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or $$self{USER}={};
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$$self{USER};
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}
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sub YYErrok {
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my($self)=shift;
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${$$self{ERRST}}=0;
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undef;
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}
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sub YYNberr {
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my($self)=shift;
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${$$self{NBERR}};
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}
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sub YYRecovering {
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my($self)=shift;
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${$$self{ERRST}} != 0;
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}
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sub YYAbort {
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my($self)=shift;
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${$$self{CHECK}}='ABORT';
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undef;
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}
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sub YYAccept {
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my($self)=shift;
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${$$self{CHECK}}='ACCEPT';
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undef;
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}
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sub YYError {
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my($self)=shift;
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${$$self{CHECK}}='ERROR';
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undef;
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}
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sub YYSemval {
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my($self)=shift;
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my($index)= $_[0] - ${$$self{DOTPOS}} - 1;
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$index < 0
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and -$index <= @{$$self{STACK}}
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and return $$self{STACK}[$index][1];
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undef; #Invalid index
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}
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sub YYCurtok {
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my($self)=shift;
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@_
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and ${$$self{TOKEN}}=$_[0];
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${$$self{TOKEN}};
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}
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sub YYCurval {
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my($self)=shift;
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@_
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and ${$$self{VALUE}}=$_[0];
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${$$self{VALUE}};
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}
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sub YYExpect {
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my($self)=shift;
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keys %{$self->{STATES}[$self->{STACK}[-1][0]]{ACTIONS}}
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}
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sub YYLexer {
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my($self)=shift;
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$$self{LEX};
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}
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#################
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# Private stuff #
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#################
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sub _CheckParams {
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my($mandatory,$checklist,$inarray,$outhash)=@_;
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my($prm,$value);
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my($prmlst)={};
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while(($prm,$value)=splice(@$inarray,0,2)) {
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$prm=uc($prm);
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exists($$checklist{$prm})
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or croak("Unknow parameter '$prm'");
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ref($value) eq $$checklist{$prm}
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or croak("Invalid value for parameter '$prm'");
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$prm=unpack('@2A*',$prm);
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$$outhash{$prm}=$value;
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}
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for (@$mandatory) {
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exists($$outhash{$_})
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or croak("Missing mandatory parameter '".lc($_)."'");
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}
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}
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sub _Error {
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print "Parse error.\n";
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}
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sub _DBLoad {
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{
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no strict 'refs';
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exists(${__PACKAGE__.'::'}{_DBParse})#Already loaded ?
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and return;
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}
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my($fname)=__FILE__;
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my(@drv);
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open(DRV,"<$fname") or die "Report this as a BUG: Cannot open $fname";
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while(<DRV>) {
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/^\s*sub\s+_Parse\s*{\s*$/ .. /^\s*}\s*#\s*_Parse\s*$/
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and do {
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s/^#DBG>//;
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push(@drv,$_);
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}
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}
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close(DRV);
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$drv[0]=~s/_P/_DBP/;
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eval join('',@drv);
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}
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#Note that for loading debugging version of the driver,
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#this file will be parsed from 'sub _Parse' up to '}#_Parse' inclusive.
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#So, DO NOT remove comment at end of sub !!!
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sub _Parse {
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my($self)=shift;
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my($rules,$states,$lex,$error)
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= @$self{ 'RULES', 'STATES', 'LEX', 'ERROR' };
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my($errstatus,$nberror,$token,$value,$stack,$check,$dotpos)
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= @$self{ 'ERRST', 'NBERR', 'TOKEN', 'VALUE', 'STACK', 'CHECK', 'DOTPOS' };
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#DBG> my($debug)=$$self{DEBUG};
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#DBG> my($dbgerror)=0;
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#DBG> my($ShowCurToken) = sub {
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#DBG> my($tok)='>';
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#DBG> for (split('',$$token)) {
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#DBG> $tok.= (ord($_) < 32 or ord($_) > 126)
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#DBG> ? sprintf('<%02X>',ord($_))
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#DBG> : $_;
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#DBG> }
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#DBG> $tok.='<';
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#DBG> };
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$$errstatus=0;
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$$nberror=0;
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($$token,$$value)=(undef,undef);
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@$stack=( [ 0, undef ] );
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$$check='';
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while(1) {
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my($actions,$act,$stateno);
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$stateno=$$stack[-1][0];
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$actions=$$states[$stateno];
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#DBG> print STDERR ('-' x 40),"\n";
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#DBG> $debug & 0x2
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#DBG> and print STDERR "In state $stateno:\n";
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#DBG> $debug & 0x08
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#DBG> and print STDERR "Stack:[".
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#DBG> join(',',map { $$_[0] } @$stack).
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#DBG> "]\n";
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if (exists($$actions{ACTIONS})) {
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defined($$token)
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or do {
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($$token,$$value)=&$lex($self);
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#DBG> $debug & 0x01
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#DBG> and print STDERR "Need token. Got ".&$ShowCurToken."\n";
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};
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$act= exists($$actions{ACTIONS}{$$token})
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? $$actions{ACTIONS}{$$token}
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: exists($$actions{DEFAULT})
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? $$actions{DEFAULT}
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: undef;
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}
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else {
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$act=$$actions{DEFAULT};
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#DBG> $debug & 0x01
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#DBG> and print STDERR "Don't need token.\n";
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}
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defined($act)
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and do {
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$act > 0
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and do { #shift
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#DBG> $debug & 0x04
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#DBG> and print STDERR "Shift and go to state $act.\n";
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$$errstatus
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and do {
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--$$errstatus;
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#DBG> $debug & 0x10
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#DBG> and $dbgerror
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#DBG> and $$errstatus == 0
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#DBG> and do {
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#DBG> print STDERR "**End of Error recovery.\n";
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#DBG> $dbgerror=0;
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#DBG> };
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};
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push(@$stack,[ $act, $$value ]);
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$$token ne '' #Don't eat the eof
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and $$token=$$value=undef;
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next;
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};
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#reduce
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my($lhs,$len,$code,@sempar,$semval);
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($lhs,$len,$code)=@{$$rules[-$act]};
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#DBG> $debug & 0x04
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#DBG> and $act
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#DBG> and print STDERR "Reduce using rule ".-$act." ($lhs,$len): ";
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$act
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or $self->YYAccept();
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$$dotpos=$len;
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unpack('A1',$lhs) eq '@' #In line rule
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and do {
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$lhs =~ /^\@[0-9]+\-([0-9]+)$/
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or die "In line rule name '$lhs' ill formed: ".
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"report it as a BUG.\n";
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$$dotpos = $1;
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};
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@sempar = $$dotpos
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? map { $$_[1] } @$stack[ -$$dotpos .. -1 ]
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: ();
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$semval = $code ? &$code( $self, @sempar )
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: @sempar ? $sempar[0] : undef;
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splice(@$stack,-$len,$len);
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$$check eq 'ACCEPT'
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and do {
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#DBG> $debug & 0x04
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#DBG> and print STDERR "Accept.\n";
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return($semval);
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};
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$$check eq 'ABORT'
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and do {
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#DBG> $debug & 0x04
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#DBG> and print STDERR "Abort.\n";
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return(undef);
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};
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#DBG> $debug & 0x04
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#DBG> and print STDERR "Back to state $$stack[-1][0], then ";
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$$check eq 'ERROR'
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or do {
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#DBG> $debug & 0x04
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#DBG> and print STDERR
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#DBG> "go to state $$states[$$stack[-1][0]]{GOTOS}{$lhs}.\n";
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#DBG> $debug & 0x10
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#DBG> and $dbgerror
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#DBG> and $$errstatus == 0
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#DBG> and do {
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#DBG> print STDERR "**End of Error recovery.\n";
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#DBG> $dbgerror=0;
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#DBG> };
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push(@$stack,
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[ $$states[$$stack[-1][0]]{GOTOS}{$lhs}, $semval ]);
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$$check='';
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next;
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};
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#DBG> $debug & 0x04
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#DBG> and print STDERR "Forced Error recovery.\n";
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$$check='';
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};
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#Error
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$$errstatus
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or do {
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$$errstatus = 1;
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&$error($self);
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$$errstatus # if 0, then YYErrok has been called
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or next; # so continue parsing
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#DBG> $debug & 0x10
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#DBG> and do {
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#DBG> print STDERR "**Entering Error recovery.\n";
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#DBG> ++$dbgerror;
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#DBG> };
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++$$nberror;
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};
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$$errstatus == 3 #The next token is not valid: discard it
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and do {
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$$token eq '' # End of input: no hope
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and do {
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#DBG> $debug & 0x10
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#DBG> and print STDERR "**At eof: aborting.\n";
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return(undef);
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};
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#DBG> $debug & 0x10
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#DBG> and print STDERR "**Dicard invalid token ".&$ShowCurToken.".\n";
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$$token=$$value=undef;
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};
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$$errstatus=3;
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while( @$stack
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and ( not exists($$states[$$stack[-1][0]]{ACTIONS})
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or not exists($$states[$$stack[-1][0]]{ACTIONS}{error})
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or $$states[$$stack[-1][0]]{ACTIONS}{error} <= 0)) {
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#DBG> $debug & 0x10
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#DBG> and print STDERR "**Pop state $$stack[-1][0].\n";
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pop(@$stack);
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}
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@$stack
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or do {
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#DBG> $debug & 0x10
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#DBG> and print STDERR "**No state left on stack: aborting.\n";
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return(undef);
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};
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#shift the error token
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#DBG> $debug & 0x10
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#DBG> and print STDERR "**Shift \$error token and go to state ".
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#DBG> $$states[$$stack[-1][0]]{ACTIONS}{error}.
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#DBG> ".\n";
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push(@$stack, [ $$states[$$stack[-1][0]]{ACTIONS}{error}, undef ]);
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}
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#never reached
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croak("Error in driver logic. Please, report it as a BUG");
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}#_Parse
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#DO NOT remove comment
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1;
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